Rotary cone drill bit



FIG. 1 is a perspective view of the a rotary cone drill bit showing our new design;

FIG. 2 is a first side elevational view thereof;

FIG. 3 is a second side elevational view thereof;

FIG. 4 is a top plan view thereof; and,

FIG. 5 is a bottom plan view thereof. 

The ornamental design for a rotary cone drill bit, as shown. 